"If you don't want to take the 40,000 you are not fit to be called Europe," he added.

Mr Juncker and Mr Tusk partially denied they had rowed, after reports Mr Juncker had declared "Je m'en fous"- I don't care – in the face of European Council concerns.

Asked about the remarks at a 3am press conference, Mr Juncker looked hurt, and theatrically moved to hug Mr Tusk, who pushed him away with one hand.

"Do not believe those who are tweeting. Do not believe those who are leaking," Mr Juncker said. "There was no conflict between us tonight."

"This conflict between us is pure abstraction," Mr Tusk added. "We are not suicidal." Mr Juncker added; "The day I will decide on suicide, he will do the same."

The row left little time for David Cameron’s scheduled presentation on plans for a referendum, described by officials as a “brief” intervention while legal drafts were prepared of the resolution on migration.

One source described it as a “commercial break”.

Leaving the summit, Mr Cameron said: “I am delighted that the process of British reform and renegotiation, and the referendum we are going to hold, that process is now properly under way.

"People always say to me these things aren't possible, that we will never get them done. Once again, we have proved we will get them done.